JP3762726B2 - Incineration ash molten exhaust gas treatment method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for treating molten exhaust gas discharged from a separate ash melting apparatus that temporarily stores incinerated ash discharged from a waste incinerator and then melts and slags it.
[0002]
[Prior art]
Conventionally, incineration ash discharged from a waste incinerator has been once absorbed and cooled by an ash cooling water tank, an ash extrusion means, etc., and stored in an ash storage means, and then carried out of the field.
[0003]
After that, as administrative guidance was given to adopt the ash melting method to reduce the volume and detoxification of incinerated ash, the classification of ash melting furnaces that came into practical use was classified as incinerators or pyrolysis furnaces. Depending on the position, the direct connection type that is directly coupled to the high-temperature incineration ash or pyrolysis residue discharge port, and the wet ash discharged from the conventional incinerator is temporarily stored in an ash hopper, etc. It can be roughly classified into a separate type that separates iron, non-ferrous metals, debris, etc., and then absorbs and cools.
[0004]
Hereinafter, regarding the latter separate type for treating the incinerated ash discharged from the conventional type incinerator which the present invention deals with, a separate type ash melting apparatus according to Japanese Patent Publication No. 7-81695, whose schematic structure is shown in FIG. A typical example of the conventional method will be described.
[0005]
In FIG. 4, a melting apparatus M is surrounded by a hearth m ₁ having a stepped gradient, a furnace wall m _2, and a ceiling m ₃ , a first preheating chamber m ₅ having a pusher m ₄ , a drop tube m _The main body is constituted by the latter half melting chamber m ₇ connected to ₆ .
[0006]
Pusher m ₄ side ash receiving hopper h in the preheating chamber m ₅ is, in the ceiling m ₃ is connected to the melt exhaust tube pm and melt air supply pipe km are burners in the ceiling portion m ₃ of the melter m ₇ m ₈ and a burner air supply pipe kb are disposed, and a secondary air pipe ks and a secondary exhaust pipe ps are connected to the lower part of the drop pipe m ₆ .
[0007]
Here, after being burned in a garbage incinerator (not shown) and temporarily stored, the incineration ash r at room temperature in which not much unburned matter remains after pretreatment such as iron removal is pushed from the ash receiving hopper h to the pusher m _4. Are fed into the preheating chamber m ₅ little by little, and are transferred to the melting chamber m ₇ on the inclined hearth m ₁ while receiving the preheating described later, and the hot burner air ab from the burner air supply pipe kb is transferred. It is heated and melted by the supplied burner m ₈ to form molten slag S, and falls from the drop tube m ₆ to the water-sealed conveyor c.
[0008]
Most of the exhaust gas generated in the melting chamber m ₇ by the heating and melting described above becomes the molten exhaust gas gm, and the unburned content in the exhaust gas is secondarily burned by the high-temperature molten air am supplied from the molten air supply pipe km. Along with the incineration ash r transferred in the preheating chamber m ₅ , the low-temperature incineration ash r containing moisture is preheated from the surface, and passes through the molten exhaust gas pipe pm to the high temperature air heater k. And discharged.
[0009]
The remaining secondary exhaust gas gs generated from the melting chamber m ₇ is subjected to secondary combustion of unburned components in the exhaust gas by the high-temperature secondary air as supplied from the secondary air pipe ks, and cooling of the molten slag S. In order to prevent the solidification, after running along with the flow of the molten slag S, it is discharged from the lower side wall of the drop tube m ₆ through the secondary exhaust pipe ps to the same high-temperature air heater k as described above.
[0010]
On the other hand, the air sucked by the melt blower b exchanges heat with the exhaust gas gm, gs discharged from the melting device M by the high temperature air heater k, and then becomes high temperature air am, as, ab. Supplied everywhere.
[0011]
[Problems to be solved by the invention]
As described above, the conventional type separate ash melting furnace removes the iron content in the wet ash discharged from the incinerator, temporarily stores the pulverized fine ash in an ash hopper, etc., and then melts separately. It is a method of melting by the heat of the furnace burner.
[0012]
Exhaust gm generated in melter m _7, the hot air heater k using gs, the thermal efficiency in order to have pre-dried the required air although improved, Shimehai r supplied is dried only from the surface Therefore, not only is the drying to the inside sufficient, but not only a great fuel cost is required, but also high-temperature corrosion of the high-temperature air heater k is inevitable because the high-temperature molten exhaust gas gm flows through the inside of the vessel. .
[0013]
Moreover, and chlorine compounds contained pyrolyzed during incineration ash r, low-boiling heavy metals volatilized and, for unburned carbon treatment generated by the combustion of the burner m _8, the exhaust gas gm and gs are the incinerator body It is necessary to take measures such as returning it.
[0014]
Furthermore, because of the preheating and drying of the ash r juicy normal temperature, it is a method of contacting with molten exhaust gm supplying the ash r in the preheating chamber m _5, is rapidly heated water contained only the surface May cause a steam explosion.
[0015]
[Means for Solving the Problems]
The incinerated ash molten exhaust gas processing method of the invention according to claim 1 is a separate type ash melting apparatus for temporarily storing incinerated ash discharged from a waste incinerator and then melting and slagging the ash melting apparatus. A melting burner at the bottom, a hearth inclined forward so that treated ash and its melt flow down, and a supply port on the inlet side of the hearth, and a slag generator is arranged on the outlet side. On the other hand, the supply port is connected to a discharge means provided at the bottom of a treated ash storage device for quantitatively storing the pretreated treated ash, which has both a quantitative supply function and a gas passage function, and the treated ash the process ash temperature has been raised in the accumulating device is configured to be dispensed, the molten exhaust gas generated from the ash melting device, the discharge means through molten exhaust gas pipe from the outlet side of the ash melting device Melting on the side And backhaul processing ash accumulating device via the gas inlet by flow through the layer of the processing ash, as well as drying and preheating the process ash, the reduced temperature exhaust gas was allowed to decrease to lead to the exhaust gas treatment apparatus It is characterized by detoxification treatment.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a block flow diagram showing an outline of a method for treating incinerated ash molten exhaust gas according to the present invention, and FIG. 2 is a sectional view showing an example of a schematic structure of a treated ash storage device, an ash melting device, and a slagging device. .
[0018]
In FIG. 1 and FIG. 2, the room temperature incineration ash 13 discharged from the incinerator 11 and once stored in the moisture absorption cooling / storage unit 12 is refined by the crushing unit 21, and then the iron / It becomes the processed ash 24 which performed the pre-process which isolate | separates the non-ferrous 23, and is introduce | transduced into the processed ash storage apparatus 3 mentioned later.
[0019]
The treated ash 24 is supplied in a fixed amount into the treated ash storage tank 32 by the supply means 31, and is dried and preheated by the backflow of the molten exhaust gas, which will be described later, in a state where a substantially fixed amount is stored by a level control mechanism (not shown). It becomes the ash 34 and is continuously discharged | emitted from the discharge means 33 which has a fixed supply function to the ash melting apparatus 4 of the next process.
[0020]
The temperature-incinerated ash 34 discharged into the ash melting device 4 is irradiated at a high temperature of about 1400 ° C. by the flame of the melting burner 41, and a small amount of remaining organic matter is combusted, and the dioxins contained therein are thermally decomposed. Both of them become harmless gases, and the inorganic substance constituting the main body gradually melts and vitrifies and descends sequentially on the forwardly inclined hearth 42 and becomes slag droplets 43 from the end of the hearth 42 to form a slag generator. 5 is dropped (see FIG. 2).
[0021]
The high-temperature molten exhaust gas 44 generated by the combustion of the organic matter remaining in the treated ash 24 and the combustion of the molten burner 41 is sent back into the treated ash storage tank 32 via the discharge means 33, and the treated ash storage tank 32. After passing through the layer of the treated ash 24 accumulated in the inside, the humidified room temperature treated ash 24 is dried and preheated, and after filtering dust, unburned carbon particles, etc. in the molten exhaust gas 44, The temperature-reduced exhaust gas 45 is sucked into the exhaust gas treatment device 6 which is mainly composed of the exhaust gas treatment means 61 and the induction fan 62.
[0022]
The slag droplet 43 dropped on the slag generator 5 is cooled or precooled by receiving a jet of water or air and then falls into a water-sealed slag storage tank 53 to be crushed into a granular or irregular shape. Cooled exhaust gas 54 stored as crushed slag S and generated by cooling the slag droplets 43 is also sucked into the exhaust gas treatment device 6 through the treated ash storage device 3 together with the molten exhaust gas 44.
[0023]
The exhaust gas treatment device 6 is mainly composed of an exhaust gas treatment means 61 such as a bag filter provided with a gas cooling means and an induction fan 62 for sucking the exhaust gas described above. The molten exhaust gas 44 obtained by thermally decomposing the harmful gas remaining therein is reduced in temperature by being sent back through the treated ash storage tank 32 and becomes a reduced temperature exhaust gas 45 in which dust is filtered. The collected ash 64 collected in the exhaust gas treatment means 61 is discharged into the atmosphere as a clean gas 63 after neutralizing, adsorbing and filtering the residual harmful gas, dust and low-boiling point heavy metals remaining in 61 and further purified. And returned before the supply means 31.
[0024]
Here, as shown in FIG. 2, the treated ash storage device 3 has a fixed quantity such as a multi-axis roll feeder made of ceramic, for example, a supply means 31 that is a fixed quantity feeder / seal mechanism such as a screw feeder. A heat-resistant material discharge means 33 having both a supply function and a gas passage function is disposed on the outlet side, and a main body is constituted by a treated ash storage tank 32 having an exhaust duct 35 at the upper end.
[0025]
Further, the ash melting device 4 is entirely constructed of a heat-resistant material, and is connected to the discharge means 33 on the inlet side of the hearth 42 inclined forward so that the temperature-incinerated ash 34 and its melt flow down. The supply port 46 is provided with the slag forming device 5 on the outlet side, and a melting burner 41 is installed on the ceiling.
[0026]
Further, in the slag making device 5, an injection nozzle 56 for injecting the cooling body 51 to the slag droplet 43 is disposed in a slag dropping pipe 55 that connects the outlet side of the ash melting device 4 and the slag storage tank 53.
[0027]
Next, a second embodiment will be described with reference to the drawings.
[0028]
FIG. 3 is a cross-sectional view showing an example of a second schematic structure related to the treated ash storage device, the ash melting device, and the slagging device. The same components as those in FIG. .
[0029]
In FIG. 3, a supply unit 37 and a discharge unit 38 which are quantitative feeders such as a rotary feeder are provided above and below the inclined processing ash storage tank 36, and a throat 47 close to the supply port 46 of the ash melting device 4 is provided. It is squeezed to seal the high temperature in the melting device 4, and a feeder 48 is disposed toward the throat 47.
[0030]
An upper end of the slag dropping pipe 55 is attached with a molten exhaust gas pipe 49 connected to a molten exhaust gas inlet 39 disposed on a side portion of the discharge means 38 in order to reversely send the molten exhaust gas 44. A cooling exhaust gas pipe 57 for flowing through the exhaust gas processing means 61 is provided.
[0031]
The supply means 31 and 37 and the discharge means 33 and 38 described in the present embodiment are merely examples, and any form may be used as long as the purpose is achieved.
[0032]
【The invention's effect】
As described above, according to the method for treating incinerated ash molten exhaust gas of the present invention, the treated ash cooled to the high humidity supplied to the ash melting apparatus is dried and preheated in advance using the molten exhaust gas effectively. In addition to improving the thermal efficiency of the ash melting device, the exhaust gas treatment is performed after the temperature of the high-temperature molten exhaust gas containing harmful gas generated along with ash melting is reduced, so there is a high possibility of high-temperature corrosion Combined with the fact that the high-temperature air heater k is not necessary, the equipment cost of the exhaust gas treatment device can be reduced.
[0033]
In addition, since the treated ash is gradually heated from below by the molten exhaust gas flowing through the inside of the bed, there is no danger of steam explosion due to rapid heating of water, and the temperature in the ash melting apparatus is stabilized.
[Brief description of the drawings]
FIG. 1 is a block flow diagram showing an outline of a method for treating incinerated ash molten exhaust gas according to the present invention.
FIG. 2 is a cross-sectional view showing an example of a schematic structure of a treated ash storage device, an ash melting device, and a slagging device.
FIG. 3 is a cross-sectional view showing an example of a second schematic structure relating to a treated ash storage device, an ash melting device, and a slagging device.
FIG. 4 is a schematic diagram showing a conventional separate ash melting furnace.
[Explanation of symbols]
3 Treated ash storage device 4 Ash melting device 6 Exhaust gas treatment device 24 Treated ash 44 Melted exhaust gas 45 Reduced temperature exhaust gas

Claims (1)

In a separate-type ash melting device that temporarily stores incineration ash discharged from a waste incinerator and then melts and slags it.
The ash melting apparatus includes a melting burner at the ceiling, a hearth inclined forward so that treated ash and its melt flow down, and a supply port on the inlet side of the hearth, and on the outlet side. While the slagging device is disposed, the supply port is connected to a discharge means having a quantitative supply function and a gas passage function provided at the bottom of the processed ash storage device for quantitatively storing the pretreated ash. Being configured to supply a fixed amount of the treated ash heated in the treated ash storage device,
The molten exhaust gas generated from the ash melting device is sent back from the outlet side of the ash melting device through the molten exhaust gas pipe to the treated ash storage device via the molten exhaust gas inlet provided on the side of the discharge means. A method for treating incinerated ash-melted exhaust gas, wherein the treated ash is passed through to dry and preheat the treated ash, and the temperature-reduced exhaust gas is led to an exhaust gas treatment device for detoxification treatment. .

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